Radiotelephone cellular service areas are typically divided among two or more service providers. Each service provider operates within a distinct frequency band which is unique to its customers. An example is the division of serving areas into two distinct frequency bands 800 MHz and 1.5 GHz serving two distinct groups of subscribers (e.g. PDC Personal Digital Cellular, a Japanese standard). Another examples is GSM (i.e. Groupe Speciale Mobile, a European Standard). These separate groups of subscribers may be served by a commonly owned but using separate and independent equipment bases to provide service area call processing and air interface service. In most cases each group of subscribers is served by a different service provider. Such is the case in Japan where different service providers serve different subscriber groups at different frequencies as presently allowed by the controlling digital cellular standards (PDC) in Japan.
As presently contemplated, by PDC, the cellular system serving each band is constructed and designed for only one band of frequency. The provision of service in each of the two bands hence requires the provision of separate and distinct mobile switching centers, base station controllers and radio transceiver units due to the division of the serving frequencies. The different services are reflected only in frequency since they both share common call processing arrangements and protocols. This requires the duplication of equipment whose only distinct feature is to function at two widely disparate frequencies.